Image guided surgery, also known as image guided intervention (IGI), is used to enhance a physician's understanding of the location of a medical instrument within a patient's body during a medical procedure. Some known IGI applications include the use of 2-dimensional (2-D) and 3-dimensional (3-D) imaging modalities. The usefulness of known techniques, however, is limited to procedures involving relatively static anatomy. In other words, the usefulness of known techniques is generally limited to use with respect to anatomy that exhibits no or minimal movement with respect to cardiac and/or respiratory cycles.
Thus, known IGI techniques have limited application, if any, in medical procedures involving dynamic anatomy (i.e., anatomy that exhibits more than minimal movement with respect to cardiac and respiratory cycles).
Moreover, known IGI systems fail to account for imaging data that includes an irregular pattern exhibited by a patient, such as an irregular pattern resulting from the application of a medical therapy to the patient. For example, in certain instances, a patient may have an irregular ECG waveform pattern as a result of implantation of a pacemaker and/or a cardioverter defibrillator lead. In another example, a patient may have an irregular ECG waveform pattern as a result of radiofrequency ablation of myocytes to cure tachycardia.
Known IGI systems can use an external reference probe to calculate a transformation between a spatial coordinate system (e.g., in the patient space) and an image coordinate system (e.g., in the image space as acquired by the imaging modality). In certain instances, such known external probes can fail to produce a desired transformation accuracy due to a moment arm escalation of error. In other words, in certain circumstances, the accuracy of the transformation of known IGI systems can be adversely affected by the distance between the target anatomy and the external probe. Although some IGI systems include a reference probe configured to be inserted into the body, such known reference probes are positioned on a proximal end portion of the instrument, and thus fail to remedy the moment arm escalation of error.
Use of known instruments in a medical procedure can result in the penetration, incising, puncturing, or otherwise accessing a portion of the patient's anatomy. Such procedures, however, can result in many harmful side effects. For example, in a procedure involving access to the patient's lung, the lung may collapse and/or pneumothorax may occur when the chest wall is punctured. Furthermore, foreign substances may enter the patient's body and/or a portion of the patient's anatomy through the site of entry.
Thus, a need exists for improved apparatus and methods for sealing an opening (e.g., a site of entry) within a patient's body. Moreover, a need exists for improved methods for using image guided surgery to seal such an opening.